Ink jet printers and disposable ink jet cartridges for ink jet printers are well known in the art. Contemporary disposable ink jet cartridges typically include a self-contained ink reservoir, a jet plate assembly supporting plural ink jet nozzles in combination with the ink reservoir and a plurality of external electrical contacts for connecting the ink jet nozzles to driver circuitry. Typically, the entire cartridge must be disposed of when the ink in the reservoir is used up without regard to whether or not the jet plate assembly remains fully functional. The contemporary disposable cartridge therefore represents a considerable waste of product resulting in higher costs to the consumer both in product cost and the time involved in having to frequently replace the cartridge.
In point of fact, the jet plate assemblies used in the currently available disposable ink jet cartridges are fully operable to their original print quality specifications after the original ink reservoir has been depleted. As a result, it is known in the art to manually replenish the ink within the disposable ink jet cartridge during the time period when the print quality from the jet plate is known to be high, but the original ink in the ink jet cartridge has been depleted. Systems in which the disposable ink cartridge are refilled are, however, messy and difficult to implement because many disposable ink jet cartridges are not designed with refilling in mind. More recently, though, some ink jet cartridges have been designed to enable refilling, such as the ink jet cartridge disclosed by Hewlett-Packard in U.S. Pat. No. 5,280,300. These refillable ink jet cartridges are designed to enable refilling of the ink jet cartridge for a certain number of refills while the jet plate is still providing high quality printing capabilities. Making the cartridge easy to refill, however, does not mitigate the bother, time, and expense involved in having to refill this cartridge frequently.
Merely making the ink jet cartridge reservoir larger in size is not a satisfactory solution to problems associated with frequent replacement of or refilling of the ink jet cartridge. The ink jet cartridges are generally mounted on a print carriage of the ink jet printer. Therefore, the larger the volume of ink in the ink jet cartridge, the greater the amount of weight that is required to be moved by the printer carriage holding the ink jet cartridges. The additional weight of ink in the ink jet cartridges will cause significant demands on the motor that drives the printer carriage. In addition, ink jet cartridges are mounted on one side of the print carriage and cause an unbalanced load on the printer carriage which requires a counter balancing mechanism. Therefore, it is difficult to balance the need for providing a larger volume of ink to the ink jet cartridges to limit the number of times that the cartridges need to be refilled with the power consumption and loading problems that larger ink volumes cause for the printer carriage.
More recently, a system disclosed by Laser Master Corporation in U.S. Pat. Nos. 5,369,429 and 5,367,328 begins with a typical ink jet cartridge, having an ink reservoir and a jet plate assembly, mounted on a printer carriage and adds an external reservoir system which refills the ink reservoir in the ink jet cartridge as the printer is printing. The system disclosed in U.S. Pat. No. 5,369,429 is designed to replenish the ink reservoir which is integral to the ink jet cartridge with ink from the external supply while the cartridge is printing. The external ink reservoir, the ink jet cartridge, and the tubing connecting the external reservoir to the ink jet cartridge are configured to form a unitary single piece replaceable assembly. The volume of ink in the external reservoir is designed to be depleted when the print quality of the jet plate on the ink jet cartridge assembly has degraded to a level that may provide unsatisfactory printing results.
Systems, such as those disclosed by U.S. Pat. No. 5,369,429, require the disposal of a large ink reservoir, an ink jet cartridge, and the tubing connecting the two once the quality of the printing from the ink jet plate has degraded. The waste and initial cost to the consumer therefore still exists for this type of system. Moreover, as the concerns over disposal of large quantities of plastic goods increases, such bulky disposable systems are not desirable. In addition, the unitary plastic assembly becomes contaminated by the ink and may not be suitable for conventional disposal. Also, the replacement of the unitary one-piece unit of the LaserMaster system is difficult due to the size of the ink reservoir. Further, the tubing attached to the reservoir must be installed in the printer with care to ensure that it is properly positioned so as to not interfere with the moving parts of the printer.
The mechanism to which the tubing of the Laser Master System is mounted is an Igus chain which is a hollow plastic chain link that moves back and forth with the motion of the print carriage carrying the tubing behind it. As the Igus chain moves back and forth, it bends back upon itself, the radius of this bend is commonly referred to as the bend radius of the chain. The bend radius of the Igus chain is large, thus the envelope of the print housing must be increased to accommodate space for the large bend radius of the Igus chain as it bends back upon itself. Further, the Igus chain does not move smoothly and makes a clunking noise as the chain link moves back and forth which is not desirable. Finally, plastic chain links such as the Igus chains are also expensive.